Since there is a nuance between an object perceived by the right eye of a person and the same object perceived by the left eye, a 3D image of the object can be further recognized by sensing the depth of the object due to the nuance, and this nuance is also referred to a parallax.
Along with the development of sciences and technologies, a 3D display technology emerges from the parallax of an object perceived by human eyes, that is, with the 3D display technology, a parallax between the left and right eyes of a person is produced artificially by feeding two images with the parallax respectively to the left and right eyes of the person so that the feeling of observing a real 3D object can be produced after the brain of the person obtains the different images perceived by the left and right eyes.
In a practical application, a birefringent lens 3D display has been produced with the 3D display technology as illustrated in FIG. 1 showing a schematic structural diagram of the birefringent lens 3D display. As can be apparent from FIG. 1, the birefringent lens 3D display is consisted of an optical thin film layer, a polarized switch and a display screen.
Specifically the optical thin film layer is composed of a single-refringent substance and a liquid crystal polymer with a positive birefringent function, where the single-refringent substance has a refractive index of n, which is the same as a refractive index n0 of the liquid crystal polymer receiving ordinary light, and the single-refringent substance is shaped in a concave lens array; and the liquid crystal polymer has two refractive indexes, one of which is the refractive index n0 with respect to ordinary light, and the other of which is a refractive index ne with respect to unordinary light, and n0 is below ne.
The polarized switch is a liquid crystal box composed of two transparent plates, to the inner sides of which, thin layers of an electrically conductive substance are attached, where the thin layers of the electrically conductive substance are coated thereon with orientated layers with orientations perpendicular to each other, and there are nematic phase liquid crystals twisted 90° between the two orientated layers.
The display screen can be a liquid crystal display emitting polarized light or another type of display with a polarization sheet.
As illustrated in FIG. 2, there is shown a schematic structural diagram of an operating principle of the birefringent lens 3D display. Specifically, the operating principle of the birefringent lens 3D display is as follows:
When the polarized switch is not driven, the liquid crystal polymer and the single-refringent substance have the same refractive index with respect to incident light, thus the optical thin film has no light focusing effect, and at this time the birefringent lens 3D display operates in a 2D mode; and
When the polarized switch is driven, the liquid crystal polymer has a larger refractive index with respect to incident light than that of the single-refringent substance with respect to incident light, thus the optical thin film has a light focusing effect, and at this time the birefringent lens 3D display operates in a 3D mode.
In view of this, the birefringent lens 3D display has the advantages of a low loss of brightness, fast switching of the 2D/3D modes, etc. However a display in the 3D mode is presented by generating the effect of a columnar lens array under the principle of the refractive index of the liquid crystal polymer with respect to incident light being larger than that of the single-refringent substance with respect to incident light and by utilizing a light splitting function of the columnar lens array to have a half of pixels perceived respectively by the left and right eyes of the person, so that the resolution of an image of the birefringent lens 3D display operating in the 3D mode can be only a half of that of the image in the 2D mode and consequently a display quality of the birefringent lens 3D display may be lowered.